Complete the equation of the line through $(-10,-7)$ and $(-5,-9)$. Use exact numbers. $y=$
Explanation: Let's find the slope: $\begin{aligned} \text{Slope}&=\dfrac{-9-(-7)}{-5-(-10)} \\\\ &=\dfrac{-2}{5} \\\\ &=-\dfrac{2}{5} \end{aligned}$ The equation is $y=-\dfrac{2}{5}x+b$ for some $b$. Let's plug the point $({-5},{-9})$ to find $b$ : $\begin{aligned} y&=-\dfrac{2}{5} x+b \\\\ {-9}&=-\dfrac{2}{5}({-5})+b \\\\ -9&=2+b \\\\ -11&=b \end{aligned}$ The equation is $y=-\dfrac{2}{5}x -11$.